Identify the tracktype corresponding to a given Codec Identifier.
When parsing a zoom-cache file, the zoom-cache library will try each
of a given list [IdentifyTrack].

The standard zoom-cache instances are provided in standardIdentifiers.

When developing your own codecs it is not necessary to build a composite
IdentifyTrack functions; it is sufficient to generate one for each new
codec type. A library of related zoom-cache codecs should export its own
[IdentifyTrack] functions, usually called something like mylibIdentifiers.

Constant or Variable samplerate.
For constant samplerate, timestamps are implied as incrementing by 1/samplerate
For variable samplerate, explicit timestamps are attached to each datum, encoded
as a separate block of SampleOffset in the Raw Data packet.